Uniaxial compressive mechanical properties and stress–strain model for roller-compacted concrete with initial damage subjected to freeze–thaw cycles

Abstract

Roller compacted concrete (RCC) often remains in a damage state as a result of improper vibrating compaction control, which makes it more susceptible to the action of freezethaw (FT) cycles in cold regions and thus results in the degradation of mechanical behaviors. In this paper, the influences of initial damage and FT cycles on the physical and mechanical behaviors of RCC were systematically examined through physical tests, including FT cycle tests, pore structure tests and uniaxial compressive tests. An in situ vibrating compaction procedure was employed in the experiment to accurately replicate the field compaction process for RCC under laboratory conditions, and the dynamic elasticity modulus (DEM) was adopted as the non-destructive testing (NDT) index to quantify the initial damage caused by improper RCC construction control. The results indicated that the higher values of initial damage and FT cycles exhibited a greater influence on the frost resistance and pore structure distribution. Remarkable attenuation of compressive strength and elastic modulus and an increase in peak strain were observed to occur in RCC when the initial damage degree exceeded 0.1 and the number of FT cycles exceeded 75. Finally, the uniaxial compressive stressstrain model was established through segmented linear regression analysis based on the Weibull-Lognormal model. The proposed model was validated to be effective and reasonable in predicting the mechanical properties of RCC under the combined effects of initial damage and FT cycles.